And a furlong is an eighth of a mile and was the distance a team of oxen could plough without resting. Literally a 'furrow-long'.
When I used to train farm-horses it was always my ambition to be able to work the unit of measurement '
furlongs per fortnight' into the conversation in such a way that people wouldn't think it was contrived. Of
course, I don't plough any more, so I've given that idea up.